Means for signaling on railways



Sept. 2, 1952 K. A. FLETCHER MEANS FOR SIGNALING on RAILWAYS 3 Sheets-Sheet 1 Filed Sept. 4, 1946 mt \Qaoumm l/VVENTOR r I'd/ id,

P 2, 1952 K. A. FLETCHER MEANS FOR SIGNALING ON RAIL-WAYS 3 Sheets-Sheet 2 Filed Sept. 4, 1946 E; m m N Sept. 2.- 1952 K. A. FLETCHER MEANS FOR SIGNALING 0!! RAILWAYS 3 Sheets-Sheet 5 Filed Sept. 4, 1946 m m mxo h M aw an Patented Sept. 2, 1952 MEANS FOR SIGNALTNG on nA LwAYs Kenneth Alfred Fletcher, Seven Kings, England, assignor to J. Burns Limited, Ch'adwell, Heath, England, a British company Application September 4, 1946, Serial No. 694,756

In Great Britain September 12, 1945 11 Claims.

y This inventionrelates to means for signalling on railways and has for its object to permit signals being received on the train in fog and other atmospheric conditions when light and semaphore signals cannot be seen by the driver of thetrain, and also to permit the Signalman to be, advised of the preserve of a train in his section during bad visibility. It does not however provide ,control over'the character of the signal established by the operator, in response to trafiicconditions in advance. v

. Signals are, transmitted between the permanent Way,.e. g.,from a signalling station (in this specification and .claims, the; term signal station or -signallingstation as appliedto my system, refers .to a box or station at which there is a signalman or attendant tosupervise and control thetrafiic onthe track) and the train, this being effected by vmeans of electronic transmitting and receiving apparatus comprising an oscillator located both in or controlled by the signalling station and on the train, the oscillatory currents employed, which are preferably of a wave length of the order of 50 cm. to m., being transmitted aselectromagnetic waves between the-permanent way and the moving train, e..g.:the cab. of theengine, by means of dipole aerials. The axes of the dipoles are arranged transversely to the direction of motion of the train. The oscillators serve both as transmitters :and receivers, for which purpose they, are each connected to an electronic or electromagnetic relay whereby the signals at the signalling station and-in the cab of the train are set in accordance with. the position of the train relatively. to points .on the permanent way, e. g. Distant, Homef? Clear. The signals set manually at thesignalling station are thus exhibited both in the signalling station and in the cab of the train, where audible signals may be actuated, or the brakes of the train set in operation or the current to the motors of ;the train cutofi. Furthermore, the presence of a train at the several signal points on the track can be indicated by appropriate signals in the signalling station.

The-dipoles on the train are caused to radiate continuously, the corresponding oscillators being energized preferably by a battery on the train; the oscillators controlled by the signalling station are advantageously energized from the power linethroughapower pack. 7 ,linesired moreover, there are provided two fl-lome signal points on the permancnt'way arranged at a suitable distance apart. 7

j By this means, when a train passes the first Home signal point, an appropriate indication will be given in the cab. As the radiating dipole on the train approaches the radiating dipoleat the second Home" signal, the output from the l oscillator acting as receiver in the cabwill gradually increase untilthe field of maximum reception is reached. Th'e'gradual increase in output current maybe measured on'a milliammeter which is advantageously provided with a red coloured portion of itsscale, so that when the from the signalling station.

The oscillator circuit for standard gauge railways may be advantageously of the Colpitts'type modified'for ultra high frequency; As a difierent frequency is advantageously used'for each of the signal points, the output to the dipole can be passed through a band pass filter to ensure that the desired frequency only shall be transmitted or received. The oscillator circuits may however be of the Barkhausen-Kurtz, linear or coaxial type, more especially with" small gauge railways and electrically driven'railways' where the space bee tween the conductor rail and one of the track rails is small. The above mentioned relays actuated by the several oscillators may consist of mechanically operated relays or thyratronvalves, the'plate currents of which energize relay coils actuating relay tongues, may be employed. The various cance1la-1 tions of lights and the automatic lighting of them are effected by interacting relays.

Each oscillator unit on the cab is advantageously built as a plug-in unit, and is fitted'with a neon lamp in. the anode circuit showing that the oscillator is functioning. Spares are carried,.and,

should the apparatus fall (the neon light consequently extinguishing), a new oscillator plugged in. Y

In the signalling station there is fitted an 11-, luminated map on which are arranged coloured lights showing the position of the signals and of the trafiic. The switching on of a signal in the signalling station connects the anode of the valve to the supply, indicated through a neon lamp on the map. The filament is alight constantly. Whilst this imposes a shorter life on the valves,

instantaneous operation is afiorded together with instant indication of a "failure- I .By means of the invention the control .of a train by signals from a signalling stationis, rendered independent of fog, rain or other adverse atmospheric conditions and certainty of operation ensured since the signal given in the signalling station is repeated in the cab and the Signalman is advised of the presence of a train in his section even when visibility is zero.

In the accompanying drawings, I have shown how mysaid invention may be conveniently and advantageously carried into practice, viz.:

Figure 1 is a diagram showing the general arin parallel with the inductance 5. The filaments rangement of the apparatus andcircuits on the.

permanent way, and in the signallingnstation Figure 2 is a diagram showingthe. general are. rangement of the apparatus and circuits onta train.

Figure 3 shows a track map provided-inchesignalling station.

neath a vehicle of the train.

Figure 5 is a view of the arrangement of an oscillator, unit with its corresponding power unit in position on the permanent way, while Figure 6 is a diagrammatic view illustrating a train carried oscillator unit and its means of connection by plug connections.

Referring first to Figure 1,7A represents the Distant dipole on the track B; C the first Home dipole; D the second Home dipole; and E the Clear dipole. F, G, G and H are the oscillators corresponding respectively to the dipoles A, C, D and E; the two Homev signal oscillators G 'and'G' oscillating at the same frequency, and the Distant and Clear signal oscillators F and H oscillating at frequencies different from one another and from that of the Home signaloscillators. These three frequencies preferably lie within the range corresponding to wave lengths in the range ofg50 to 500 cm., for example, the middle, frequency, e. g. for the Home signals, may be 200 n egacycles corresponding to a wave length of lEQgcms; If desired these three frequencies may be stabilised by passing the oscillatory currents through corresponding filters J., Each of the oscillatorsissupplied with current through a power pack Kgfedfrom a power line L. The oscillators, when acting as receivers, actuate relays H at the signalling station through conductors M whereby electric lamps [9 at the signalling station may be energized (as hereinafter described) fReferringto Figure 2,'Q, R,"S'are dipoles arranged beneath the cab on a train and connected respectively to oscillators T; U, V;'the se oscillators being; tuned respectively to the Home, Distant and Clear frequencies, i.-e. to the same frequencies as the track oscillators (G, G), F'and H respectively. The oscillators T; U;'V'are also,

if necessary, provided with filters J between themselves and the dipoles Q, R, S. The oscillators T, U,'V are also connected through relays W;X;1Yto Home, Distant and Clear signals on a repeater'panel I and are provided with suitable interlocking circuits as hereinafter described, In addition, the circuit of the Home signal relay coilj W includes a milliampere meter Z, .the. pointer of which is arranged to move from a zero corresponding to the value of-the rest anode current of the Home signal oscillator T, e. g 10 milliamperes, to higher values, e. g. 14 milliamperes, as the train moves towards a Home signal dipole. The Home oscillator T through its relay W'may also be arranged to, operate thebrakes of the train by means of a relay 2; The oscillators T; U; V are energized from batteries 28 on the train through a'common power pack 3.; q

" Describing the apparatus now in more detail;

of the cathodes 8 are preferably heated directly fronnthe battery 28 on the train. In the case of the oscillators on the track, the cathodes may be heated fromtheipower packs K which may conveniently be housed in units In arranged beside the track, as illustrated in Figure 5, such units being-connectedtofurther track units ll each housing-the oscillator and dipole for the respective signal point, the dipoles being arranged transversely to the direction of motion of the trains. Thearrangement of the dipoles below the train may be effected as showrrin- Figure 4, the: connection between the oscillator T, U" or V- andthe corresponding dipole being; made-by means of a coaxial feeder 12 having a suitable impedance.

The resistance of-the grid leak resistor :91 of the train-carried oscillators-ismade suchthat when there is-no coupling between-train and track oscillators, only weak oscillation of-thc train-carried oscillators occurs.- The value of the anode current under this condition istermedthe rest anode current. When thedipoles of the train-carriedoscillators pick up additionalr energy from the track oscillators, the anode current is increased. By reason also of 1 the loose coupling obtained with the dipole aerials'rthe anode current of-the oscillating units will'not. be affected by the presence of-unenergized oscillators on the track and the train-carried oscillatorswill act as super-regenerative receiversi The oscillators of thesignal dipolesA -ic DpEi on the track are energized'by closing their energizing circuits by means of interlocked switchesi3 (Figure l), whereby'signal lights l4,'consist+ ing preferably of neon lampsshuntedxby resistances l5; are lighted and appear on, the track map it (Figure 3) to indicate that "thecorree, sponding oscillator-is in operation; The current; in this circuit passes through the coil ofathe relay. ll, the said coil'being so wound that it doesnot move its tongue until additional energy..-is re-, ccived from the corresponding track dipoleiwhen' the dipole on the train: is in 'close proximity, thereto. The relay tongue then-closes a circuit, it including a signal light 19;-which thus. indi-. c'ate the positionof the trainonthe track map. is (Figure'B). Thesw-itches' J3Jare interlocked by means of a bar 42 which is arranged so. that; the switches controlling the; Distant and; Home; oscillators are automaticallyjopened when; the switch controlling the- Clearwsignal oscillator is.

closed. I

On the train,- the actuating-coils .of, thatrelays W, X, Yet the Home, Distant and Clear: signals respectively, are each'series connected in. the anode circuit of the correspondings-voscillatorra, neon or other suitable indicating lamp .23sshuntedby a resistor Zap-beingalsoarrangedinseries in said circuits in order-togive: a :continuous'ine; dication that the respective oscillatori in opera-r tion;

These circuits are also interlocked-in-order-to prevent the Distant and Home signals-inethe cab from being extinguished Y until the Clear signal switch has been-operated-at the-signalling-st'a-= 51' tion. The relay Y of the Clear signal has two relay tongues 25, 2%, which are moved .simulta-.

neously when the relay-coil is energized. When this relay is energized, the tongue 25 opens a circuit 2'! including .the battery 28, normally closed contacts controlled by the tongues 29, 3ll

of the relays X and W, and the Clear signal on the panel l. The energization of the relay Y also causes the tongue 26 to open a circuit 3| including the actuating coils of the Distant and Home Sig-' the tongue 29, actuates a further tongue 32 cone.

trolling apair of normally open contacts inl'a circuit 33 which also includes the battery28, the Distant signal on the panel I and a pair of normally. closed contacts controlled by another tongue 34 of the Home signal relay W.

The relay W when energized, closes, by. means of a tongue 35, a circuit 36 including the Home.

signal on the panel I and the battery. 28, and a circuit 31 includingthe actuatingooil of the brake operating relay 2 and the battery 28. Energiza tion of the relay W also results in the opening of the pair of contacts previously described in the circuit 33 and. controlled by the tongue 36;and in :the opening of the contacts previously de-. scribed in the. circuit 21 "and controlledbythe tongue 35.

The relays X and W are constructed to retain their tongues in the attracted position by reason of'the rest currents of the continuously energized oscillators U and T, when energy is no longer received from the corresponding oscillators F and G, G on the track; although this is not .the case with the relay Y, as aforesaid. Figure 6 shows an. oscillator unitT, Uor V adapted to be connected to thedipole, battery and other circuits on the train by means of plug socketsilfl, M, a coaxial type plug 38 coupling the.

aerial Q, R or S atfiil and a multipin type plug 39 coupling the remaining connections at 41:. The said plugsare arranged at the rear of the units and'the sockets 40, M at the rear of the recesses inthe cab designed-to house the oscillator. units;

The. apparatus operates as follows: 1 1 Assuming that the section of the track in front of an. advancing train is clear, the rest current of-the oscillator V on the train controlling the. Clear signal, e. g. a green light, will not energize;

itsrelay Y suficiently to open the contacts at 25, 26,-so that the circuit2l controlling the green Clear signal'lamp on the panel I is and thus a green light is shown.

When the train reaches a section of. the track controlled by a set of signals, and the way is not clear, the Distant signal oscillator F is operated. from thesignalling station and received by the gized) and, the relay W is operated, the. ammeter notj'broken Z simultaneously showing a high-readingflpnirg; ation of the relay W opens the circuit 33.;by.

means of the tongue 34 thereby cancelling the Distant light, and simultaneously closes thecirp. cuits 36 and 31 by means of the tongue 35. The circuit 36 lights up the Home signal on thepanel l, and the circuit 31 operates the brakecontrolling relay 2.

The second Home signal dipole is placed at Home signal dipole has begun tofall, againrises and reaches a peak value as indicated by the upper coloured portion of its scale, i. e; when the train diploe Q and the track dipole Dare a minimum distance apart. The relay W-remains energized and the Home signal on the panel I therefore remains alight, since as stated above the relay W is retained by the rest current in the oscillator T. This creeping forward to the second Home dipole allows the engine to be in the best possible position to receive the Clear-signal, the dipole E for which is placed within two feet approximately of the second Home signal dipole D. When the dipole E is caused to radiateby its corresponding switch l3 being closed, the-Dis-- tant and first and second Home signals are automatically switched off by means 'offlthe interlock ing bar 62 and their corresponding switches l3; The reception of this signal in the cab of the train energizes the relay Y which through i'ts tongue 26 opens .the'circuit 3i through whichthe coils of the relays W and X are supplied."

These relays are thus restored to their original positions the Home signal light being cancelled and the needle of the ammeter again falling. The green Clear light is reinstated when the relay Y is deenergized again, for which purpose the Clear signal current from the signalling stationis cillators, means for energising said oscillators,"

signalling devices on the train,

relays connected in the anode circuits of said oscillators and controlling the circuits of: said signalling devices;

and on the track, an oscillator at eachJsignal.

point corresponding to one of the oscillators on the train, the corresponding train and .trackoscillators operating at the same frequencies, :a dipole antenna having its axis arranged transversely to .the direction of the track for each of:

said track oscillators, means controlled from a. signal station for energising said track oscillators, first signalling devices at said signalling:

station adapted to be actuated by the hormalcur rentsin the energising circuits of said track oscillators, second signalling devices at said sig-f nalling station adapted to be actuated by'greater currents than such normal currents, :which;

greater currents result from the proximity of an energised train-carried dipole to a traclrdipole; and electrical connections between the. :respec 1 tive. track oscillators and the. corresponding first between the plate of the said triode=electron tube the sig al;sta tion :Iorg energising. ;;said track oscillotorsnfiistsienalline devices .at said signalli-ne tation adapted tote actuatedbythe normal cur: rents in;the energisingcircuitsaof said track oscillators second signalling-;. derices at saidcsig- 25 nallinsl atio edept dtcteactuatfiid y; eater cunrents;than such;normal currents, which greate nlnurreats: r u t ir m h pr of n enengisedqtrainecarried, dipole: to a track-dipole, ndifi eflffiricalconnections-between the respectire-traclr; oscillators-and the corresponding first nd. second sie el ine devices at the na n station); Whereimtheoscillators are of a modified Colpitts ,typa comprisinge triode, electron tuoe. aicircuit comprising an inductance connected .in parallel withaline consistingi-oflwtwo condensers arranged in series, a connection s between, the cathode of the triodeelg tronltube anda point e ween s id. condens rs; .an auto-bias c mpri e inga gridcondenser and a gridleak resistorto the glld'of said triodeelectron tube, a connection including the condenser of the autos-bias lac-- tween the grid of the triode electron-tube and one"endof-- the-said inductance; a --conneotion and the other end of said inductance, a :tuning condenser connected in parallel. with said inductance, and a radio frequency choke; con.- nected to a tanning pointon: said inductance;v c

3. Apparatus .for signalling, on railways come, prisingon the train .a series-0f oscillatorstcapabletof radiating and receiving separatezunmodur, lated;:e1ectromagnetic; waves of. different radio;v frequencies, an antenna. consisting of a dipole; having its: axis arranged-transversely to the'wdiviz rection of motion of the trainicr each-.ofzsaid; O oscillators -rncam for energisin'g; said oscillators; signalling devices; on: the train, ire-lays. connected-1 in. the anodelcircuitsof said oscillators-and con;- trollinguthe circuits oisaidisignalling devices.; andzon 1 the :track,v an oscillator: at-;eachsignal 60 p int-. rrcspondingetc one ofrthei oscillators-om the train; the correspondingtraingand track; 05;; cillators operating atrthe same1 =freeuencie ;;.a; dipolecantenna having, its:- axis arranscd- :transversely' tozth direction :of the trac k. Lior; each; oi; said track ;oscillators; gmeansc controlled from; :a 4 signalstationifor energisingsaid nack1oscil1ators,.: first: signalling-devices iatsa-id signalling stations. adapted ;to be actuated: by the normal: currents; in-the energising' circuits of said track oscillators, second signalling devices at said signallingcstae; tion' adaptedto be actuated by greater currents; than-such i-normal .;currents;. which igreatericure'.

rents resultctromzthe proximity :of; an energisedi 757 quencies zaniantennai consisting: fl dipole, a e;

d-trackoscillators; means controlled from.

traineoarrlemdipoleito saztraclridipoler, and else-c tri'catfconnectionsnhetween' the respectivestrack: oscillators and :.the acorresponding. :first; and-:sece,- and signalling :idSViCES. at the=.:signallingstation; wherein the train-carried oscillators each ;com-.- priseea gridglealciresiston of :such .zva'luez that only; wealraoscillationscnormally occur, the :value 10f; thei. anode scurrent rounder. :thiS condition being; termed the =restranode -:cu-rrent, and so that, if thesdipolei aerialsmf the train-carried oscillators 1 pick upgadditionalienergy;from the; track. oscil-- latorszthe. anode; currentiisrincreased 4.; Apparatus zzforusignalling a on railways com-- prising onzthetrainca seriesiofgoscillators capable-1 ofzradiating andreceiving.separateunmodulateda e1ectrcmagnetic..:; waves; :of 1;; different vradio ;fre-,--; quencies, an antenna consisting of a dipole have in'g itsgaxis; -ar:ranged :transrersely to thewdirectionaofxmotionzoiztheaitrainzfoneachioflsaid osr: cillators, 1 means ufortenergising; said oscillators; 1 signallingadeldces onzthez trairnvrelays connected: inthe-anodezcircuits of-saidoscillators and com.- trolling. the. circuits. of said signalling devices; and Jon the track-,- :an: oscillator: at each signal point correspondingto: one-of the. .oscillatorsconr the; train,*the. correspondin .train anditrack. os-

cillators operatingnatx the same. frequencies, a dipole: antenna :having :it; axisarranged trans versely to: the, directiomof the:track1for each of J said. track osci11ators;:.means:i controlled from: a signalstation foreenergisingesaid track oscillators;.: first signalling; .devicesat; said signalling station adapted to' be; actuated by the; normal currents inithelenergisingicircnits of :s'aidtrackoscillators;s

second-(signalling ;devices at. saichsignallingestaa tion adapted to be actuated by greatencurrents: than asuch Enormal currents, which greater-Jourrentszresult :from the; proximity; of: an energised: train-carriedfldipolei to: a :trackidipole; and elece trical' connectionsubetween the "IESDBCti-VG-"TIQCKJ: oscillators and ,thencorrespondingifirst: and sec."- onchisignallingiidevicesiatythe signalling station; wherein on the trainithereiaaClearisignahca Distant. sighaliand a Home. signaL; .relays' controllingcthacircuits iof' the.Cleansignal;thee-Dies:

tant: signal t and the ziHorne signal respectivehm series-connected :icontactorson :each of v the: said 1 relays,-:whichqcontactors are. closed when thetaree; lays; are; in their: normalzdeenergised positionoso: asitorilliiminate'rthez Clear signal; a normtallnopens contactor: on :the :Distantsignal Lrelaw. amore: mallyl'closed .contactor'onthe :Homesignal relay: connected in seriesgwithxtlierlast mentionedsnormally: opemrcomactorpwhich contactorg servezto illuminateathe: Distant signal when the Distant relay energised; at currentcmeter connected: in series witlnthe coil: of :the Home.asignalzirelami so astosindicateithe degree of energisationithere-o of; a normally closed conta'ctor .on: the Clear sigi-t. nail/relay; .iwhich conta'ctor is. connected inserieswith the coil of the;.-Home signal: relay 'andiin'z series withlthecoilnf theDistant-signal relay, so;aszto:prevent'cenergisation of the Distant-and: Homesi'gnal-relairsazwhenthe: Clear signal: relayis; energised a normally open 'contactor on :the Homeisi'gnal-zrelay in series connectioir'with tlie Home:-.signal,i. adapted to: illuminate said Home: signal-soir-energisation:of :the' Home: signalrelay; 1 and a source ofielectrictenergy connected'totsaid signals and to'said contactors; I

'5. i Apparatus. for i signalling on. railways-comprising;on. thetrain a series of oscillators capable of; radiating; and: receivin separate unmodulated electromagnetic :wavesa-oi different radio ires:

, 9 ing its axis arranged transversely to the direction of motion of the train for eachof said oscillators, means for energising said oscillators, signalling devices on the train, relays connected in the anode circuits of said'oscillators and controlling.

the circuits of said signalling devices; and'on the track, an oscillator at'ea'ch' signal pointcorresponding to one ofthe oscillators on' the train,

I the corresponding train and track oscillators operating at the same frequencies, a dipole antenna arrangement including two home signalantennae spaced apart from each other andhaving itsaxis arranged transversely 'to' the direction of the track for each of said track oscillators, means controlled from a signal station for. energising said track oscillators, first signalling devices at said signalling station adapted to be actuated by the normal currents in the ener'gising circuits of said track oscillators, second signalling devices at 7 said signalling station adapted to be actuated by electromagnetic waves of difierent radio-frequencies, an antenna consisting of a dipole having'its axis arranged transversely to the direction of motion of the train for each of said oscillators,

means for energising said oscillators, signalling devices on the train, relays connected in the anode circuits of said oscillators and controlling the circuits of said signalling devices; and on the track, an oscillator at each signal point corresponding to one of the oscillators on the train, the corresponding train and track oscillators operating at the same frequencies-a dipole antenna having its axis arranged transversely to the direction of the track for each of said traclgoscillators, means controlled frorna signal station for energising said track oscillators, first signalling devices at said signalling station adapted to be actuated by the normal currents in the energising circuits of said track oscillators, second signalling devices at said signalling station adapted to be actuated by greater currents than such normal currents, which greater currents result from the proximity of an energised train-carried dipole to a track dipole, electrical connections between the respective track oscillators and the corresponding first and second signalling devices at the signaling station and switches arranged at the signalling station, said switches controlling the supply of energising current to each of said oscillators at the signal points on the track.

7. Apparatus for signalling on railways comprising on the train a series of oscillators capable of radiating and receiving separate unmodulated electromagnetic waves of different radio frequencies, an antenna consisting of a dipole having its axis arranged transversely to the direction of motion of the train for each oi said oscillators, means for energising said oscillators, signalling devices on the train, relays con nested in the anode circuits of said oscillators and controllin the circuits of said signalling devices; and on the track, an oscillator at each signal point correspondin to one of the oscillators on the train, the corresponding train and track oscillators operating at the same frequeni on the train.

" cies, a dipole. antenna having its axis arranged oscillators, firstzsignalling devices at .said signalling station adapted to be actuated by the normal currents in the energising circuits of said track oscillators, second signalling devices at said signallin station adapted to be actuated by greater currents than such normal currents, which greater currents result irom'the' proximity of an energised train-carried dipole to a track dipole, electrical connections between therespective track oscillators and the corresponding first and second signalling devices at the'signalling station, and a wave filter arrangeddn circuit with each of the dipoles on. the tracka'nd 8. Apparatus for signalling on' railway "comprising on the train a series of oscillators capable of radiating and receiving separate runmodulated electromagnetic waves'of different radio frequencies, an antenna consistinglof' a dipole ha ving itsaxis arranged transversely to the direction of motion of the train for each of said'oscillators,

means for energising said oscillators,-signalling devices on the train, relays connected .in ;the anode circuits of said oscillators and controlling the circuits of said signalling devices;.and* on the track, an oscillator at each signal'ipoint corresponding to one of the oscillators on Sthe train-the corresponding train and track oscillators operating at the same irequencies; adipole antenna having its axis arranged transversely to the direction of the track for each ofsaidttrack oscillators, means controlled from: a signal stasignallin devices at said,'signalling -station adapted'to be actuated by the'normal currents in the energising circuits of'said; track oscillators,

second signalling devices at said signalling; station adapted to be. actuated by greater'ou'rrents than such normal currents, which greater-tour rents result from the proximityv of anaenerg'ised train-carried dipole to a trackdipole, and 'electrical connections between the respective track oscillators and the corresponding first and second, signalling "devices at the; signalling "station, wherein on the train there is -provided asig'naL- ling device, consistin of an electric lamp shunted by a resistor in the anode circuit of each oscillator.

9. Apparatus for-signalling on railways comprising on the train a series of oscillators capable of radiating and receiving separate uninodulated electromagnetic waves of different radio frequencies, an antenna consisting of a dipole having its axis arranged transversely to the direction of motion of the'train for each of said oscillators, means for energising said oscillators, signalling devices on the train, relays connected in the anode circuits of said oscillators and controlling the circuits of saidsignalling devices; and on the track, an oscillator at each" signal point correspending to onejof the oscillators on the train, the corresponding train and track oscillators operating at the same frequencies, a dipole antenna having its axis arranged transversely to the direction of the track for each of said track oscillators, means controlled from a signal station for energising said track oscillators, first signalling devices at said signalling station I 1 iftionw adapted to i be: actuatedmy; greater currents tethan: such 1 normale currents, i which i greater rear- 5 ronts result-from itheaproxim-ityi of: an energised rztrainecarried dipole to: a :track i'dipolcg: and; elec- '-;trical LGOHHECtiODSL-IJQtWGEHi the -respective track oscillators andthe correspondingfirst' and; :sec-

r: brrdcsignallingi devices; at 'the signalling: station,

cwherein.;the signalling: devicesat theusign'allin station adapted-tome, actuated; by the normal prerating currents in :the energising: circuits of the;

=,,traclr.oscillators;;.eachrconsists of aneelectric lamp ,alshuntediby; a resistorarranged ineach said energising: circuit.

igilfleApparatus fonsignal-ling. on-srailways-comprising on the train aseries: of oscillators capable, :rnf radiating and receiving separateunmodulated electromagnetic waves :of different radio :frequencics, an antenna consisting ofraidipole having; its; axis arranged-transversely v to the 1 direc- :fbiflll Of motion-.of thertrainfor each. of said oscil- ;=letors;=meanssforzenergising :said oscillators, sig- "nailing; devices: 1 ontthe train, relays aconnected rcitrollingthe circuitswof ;:said signalling -:devices;

- and-.-on:.=thewtrack ane oscillator: at each signal pointzcorresponding to zone: of the oscillators .on ;the strain, :the :-.corresponding trainv i and vtrack :nscillators operating at* the r same "frequencies, :.a dipole antenna-having its; axis arranged trans- 'werselyi to the, directionofthetrack for each of :saidtrack oscillators, means controlled -from a signal station it-fon. energising said track oscilclatorssfirstwsignalling IdGViCSS at said signalling estationr adapted" tOrl'be actuated; by the normal ecurrentszin the: energising circuits:0f said track --0.scil-1ators,:second signalling devices at said :slgnalling station adapted tdbeactuated by'greater warrants -:zthan vsuch normal currents, which .sgreater currents--result"'irom-the proximity of ranenergised:trainecarried'idipole to? a track dir poleiyand electricalconnections between the rei-spe'ctive :t-raclr aoscillators i and the corresponding enrstxandsecond signalling devices at'the-sigr' nalllng--.-station,-awherein the signalling devices atrthevsignalling station adapted to be actuated 12 1e.:furthermircuit;:lnclndingrasonrcmoaelectric irenergy;.and'lanielectricrlamp. 1 .7

..ll..aADDaratus for signalling:onwailwaysrlcom- 1 prising on;the;trainta series. of; oscillators capable 5 of radiatingrand; receiving. separate .unmodulated -;e1ectromagneticwaves of -...difierent. radio :frenuencieacan antenna consisting .ot a: dipole haying itsraxis; arranged ntransrerselyc.to the; direction of motion of. the:train for sachet said oscillators, means. for:.energising-;said; oscillators,; signalling devices: onrthez train: relays connectedzin the anode circuits-ct said. oscillatorsrand: controlling the; circuits;=of;- said signalling-devices;;-.and. ion :ctheirack;anhoscillator at each signal pointcorresponding to oneofthenscillators .onrthe train. :the. :.correspnnding; train and: track. oscillators operating:atithe rsame freeuenciese aedipola an- :.tennahavingiitsraxisarranged,itransrerselwto litheidiIGCfiQH-J.ofiithelrti'aick1013Ch50f1531id track i-zoaosciliators, means1controllechimm-calsienalstajionnior energisingvxsaid;;track,,.oscillators,:first :rsignalling -;;de1r.ices rat :said z'signallingr station adapted ltaheactnatedby thanormalcurrentsin 4 theener ising circuits: ofrsaid track oscillators,

V zs'xsecond'asignalling devicesat; said signalling, sta- 55111 unscillatorlmay be r readily: replaced when :necessary. 7

JKENNEIEHALFRED 'EEEI'CHER.

:REEERENCES ,CITED 'ihevfollowing-references areso'f record -in the -file =of-1this patent:

" UNITED STATES PATENTS Number @Name Date 928,004 Prochaska July1 3,,.1-909 0 1,484,049 Zw,orykin rFeb. $19, 1924 1,610,692 Logwood Dec. 14, 1926 1,815,628 Williams. et a1 July. -28, 1931 2,1.31 042 'Halstead Sept. .27, 1938 

